Not much left, and it is an quite cool game you can download and try in its older form right now.
Once it is updated to the new open-source vesion of the Torque3D engine (http://www.garagegames.com/products/torque-3d ), it could become a quite awesome fully open-source online FPS and a cool play-ground to test alternative game-play modes and models etc.
More Tribes2 like gameplay would also be cool (and it is the original Tribes2 engine afterall, although much improved).